Noticed games on here with error exceptions on them....latest is bright past 05. Is that cause of the window version they use to mine or is the load crap?
There's many, many, many reasons why a Ren'py game (since the example you used is one) can throw an exception. The difference between author's OS and yours is never one of them.
It can be because it's a lot of crap, or it can be because the author don't know how to deal with save compatibility ; like it can also be because he hadn't the time to test every single possibilities.
If the author is member of the forum, the best solution is to report the problem in the game thread, while tagging the said author.